Electrical installations in an aircraft require special cables and special cable connections for protection against electrical overloads that may be caused by lightning. For this purpose the cables are encased by electrically conducting hoses and the electrical conduction must not be interrupted by cable connectors that either connect two cables to each other or a cable end to a housing of an electrical component in the aircraft. A substantial number of such connectors must be installed in very little space. The installation could be facilitated if connectors were available that provide for a relative movement between connector components without interrupting an electrical grounding path.
German Patent Publication DE 3,914,930 C1 (Kirma) published Oct. 25, 1990 discloses a plug-in connector of straight construction. A protective hose is rotatably secured to the connector in a force transmitting manner. While the rotatable connection transmits mechanical forces, it does not provide an electrically conducting connection between the electrically conducting protective hose and the plug-in connector. An interruption of the electric grounding path by the connectors is undesirable because it prevents the proper dissipation of overloads into the metal structure of the aircraft. Thus, the construction of the connector according to German Patent DE 3,914,930 is suitable only where a mere mechanical rotatable connection of connector components is satisfactory.
German Utility Model Publication GE-UM G 94 01 199.0 (Sihn, Jr.) published May 5, 1994 relates to a coaxial cable fitting for connecting a coaxial cable to a housing. The housing has a connector bushing with an inner threading. The fitting has an outer conductor bushing with a device for holding the coaxial cable in the outer conductor bushing which has an outer threading for cooperation with the inner threading of the housing connector bushing. The device for holding the cable is a shrinkable hose and the mentioned outer threading is part of a section rotatably connected to the outer conductor bushing. A separate contact spring is provided between the outer conductor sleeve or bushing and the threading bushing. Separate contact springs leave room for improvement.
German Utility Model DE-G 93 06 608.2 (Interconnectron) published on Nov. 4, 1993 discloses a contact mechanism for the metal webbing hose of shielded cables. A helical ring-shaped spring is used to encircle the metal webbing of the protective hose. German Utility Model DE-G 92 04 291.0 (ABB Patent GmbH) published on Jun. 17, 1992 discloses a lead through connector for passing a cable through the wall of a housing. A contact washer with spring elastic metal prongs is inserted into the connector. German Patent Publication (DE-OS) 3,412,824 A1 (Gengenbach et al.) published on Oct. 17, 1985 discloses an electrical load switch suitable for switching in a medium voltage range. The switch comprises a contact bushing that is closed at one end and slotted at its open end so that axially extending prongs are formed. The free ends of the prongs are provided with radially inwardly extending projections for improving a spring contact to a pin that is inserted into the bushing.
German Patent Publication DE-AS 2,046,231 (McKnight) published on Apr. 1, 1971 discloses a lead-in connector for securing electrical conductors to a housing in a way that the conductors are relieved of tension stress. A coupling nut is rotatably secured to a stress relief member with the aid of a spring ring that engages both the coupling nut and the stress relief member. Once the coupling nut is in the proper position it is secured with a set screw. The German Patent Publication 2,046,231 is based on U.S. Ser. No. 859,923, filed on Sep. 22, 1969.
German Patent (DE) 2,937,731 C2 (Spinner) published on Mar. 19, 1981 discloses a coaxial high frequency plug-in connector. A bayonet type coupling is provided and the coupled state is maintained by a Belleville spring packet.
The conventional constructions discussed above are not suitable for use in an aircraft electrical installation where, in addition to the mechanical and electrical connections, an electrical grounding path must be maintained.